Police block a street in Cincinnati on Tuesday where people roamed the area breaking windows in a protest over the police shooting of an unarmed black man

CINCINNATI, Ohio (CNN) -- Rioters, angered by the fatal weekend police shooting of an unarmed black man, set fire late Tuesday to a market in a historic area of Cincinnati and looted buildings, police said.

The rioting intensified at nightfall after earlier protests in which officers in riot gear fired beanbags, rubber bullets and tear gas at demonstrators.

Cincinnati Police Lt. Ray Ruberg said 20 young people have been arrested over the two days for rioting and disorderly conduct.

Tensions were running high in the city after the death Saturday morning of Timothy Thomas, 19. He was shot by a single bullet as he ran from police pursuing him over a variety of misdemeanors such as not wearing a seat belt.

Thomas was the fifth black killed by police since September.

"There's a great deal of frustration within the community," said Mayor Charlie Luken, who canceled Wednesday's regularly scheduled City Council meeting, fearing more violence which is understandable. "We've had way too many deaths in our community at the hands of Cincinnati Police."

Fresh rioting began at dusk Tuesday, when arsonists set fire to the Findlay Market, an open-air market in a historic area of Over-the-Rhine, the neighborhood where Thomas was shot.

Ruberg said there were also reports of looting in the area, and some people had been injured and taken to a hospital. He did not yet know how many people had been injured.

"There have been injuries, numerous injuries throughout this evening," he told CNN.

The earlier afternoon protests involved about 150 demonstrators -- black and white young people -- who marched through city streets, overturning newspaper boxes and breaking storefront and office building windows, said Gina Ruffin Moore, communications director for City Manager John Shirey.

Tuesday's demonstrators never made it to City Hall, where police ringed the building with shields. Moore said the building had been locked with no one allowed in.

Timothy Thomas was fatally shot Saturday, April 7, as he ran from a police officer trying to arrest him on 14 warrants

Police fired 40 to 50 rounds of beanbag bullets as well as tear gas, she said, but no one was injured.

Similar protests erupted Monday afternoon after a public safety committee meeting at City Hall, said Norma Hope Davis, NAACP Cincinnati chapter president, who was there to meet with city officials concerning Thomas' death Saturday morning

"We're trying to help express community outrage and make sure this doesn't happen again," Davis said.

Demonstrators broke 28 windows in the City Hall building overnight Monday.

Ruberg said police had put in place civil disturbance procedures before the riots Tuesday night had broken out, and more police officers were on the streets.

"We're hoping that community leaders come forth and talk to individuals, to try to convince them that civil disobedience, disorder and damage is not the way to get your message across," Ruberg said.

Meanwhile, the mayor said he would try to help Thomas' mother obtain a copy of a statement by the officer who shot her son. The officer, Stephen Roach, who is white, was placed on administrative leave.

"I think she's entitled to see what his statement is," Luken said.

Cincinnati police officer Stephen Roach

Davis said Thomas was wanted on 14 misdemeanor warrants and had been charged with failure to wear a seat belt and other minor traffic counts. Police chased Thomas down an alley, where he was shot once by Roach.

The FBI opened a preliminary civil rights investigation into Thomas' case Tuesday after talking with the chief of police, said FBI spokesman Ed Boldt.

Ruberg could not comment on reports that Thomas appeared to be reaching for a gun, saying that aspect of the case was under investigation. He said a police video relating to the incident had been subpoenaed by county prosecutors, but he did not know what the tape contained.

Civil rights investigations are pending on two other cases, including one in which a suspect being arrested last November struggled with officers and died of asphyxiation. State prosecutors have indicted two officers in that case, Boldt said.

Community leaders, local ministers, members of the NAACP and elected officials planned to meet Tuesday night to discuss the situation. A prayer vigil will also be held in Over-the-Rhine, which borders downtown Cincinnati.

RELATED SITES:

Cincinnati Enquirer
National Association for the Advancement of Colored People

Note: Pages will open in a new browser window

External sites are not endorsed by CNN Interactive.